Where is fast driving particularly dangerous?

Your answer is completely correct. Fast driving is especially dangerous at blind corners because you cannot see oncoming traffic or obstacles in time to react safely. At road narrowings, the reduced space increases the risk of collisions, so driving fast leaves little room for error. At level crossings, fast driving is risky because trains approach quickly and may be difficult to spot, requiring ample time to stop safely. In all these situations, slower speeds help ensure you can respond appropriately to hazards and avoid accidents.